Rinse aid formulations generally are aqueous solutions containing nonionic surfactants which promote rapid draining of water from dishware and minimize spotting-and-filming. Under conditions of high total dissolved solids, surfactants alone will not prevent filming. It is known that polymers of acrylic acid can improve the performance of rinse aid compositions by inhibiting deposition of mineral salts which contribute to filming of dishware.
EP0308221B1 discloses a rinse aid composition containing a low foam nonionic surfactant, an acrylic acid polymer of molecular weight 1000 to 250,000, and an additional nonionic surfactant having a cloud point of at least 70.degree. C. to serve as a stabilizer. U.S. Pat. No. 4,678,596 discloses a rinse aid composition containing a low foam nonionic surfactant, a low molecular weight poly(meth)acrylic acid, and a high molecular weight stabilizing polymer of methacrylic acid.
Finally, U.S. Pat. No. 4,203,872 and U.S. Pat. No. 4,264,479 disclose surfactant compositions comprising (a) 25-75% nonionic surfactant, (b) 5-65% amphoteric detergent such as an alkylaminodipropionate, (c) 8-50% quaternary ammonium halide, (d)water. Said compositions are useful in preparing cleaners and degreasers, glass and smooth surface cleaners, wax and floor finish strippers, and soap film removers.
Applicants have now surprisingly discovered that the addition of certain alkyl iminodipropionates stabilizes rinse aid compositions without the need for a high cloud point nonionic surfactant or compatibilizing polymer for stability.